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Wilasinee Pakviwat - One of the best experts on this subject based on the ideXlab platform.
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Fracture Resistance of endodontically treated teeth three walls versus four walls of remaining coronal tooth structure
Journal of Prosthodontics, 2009Co-Authors: Siriporn Arunpraditkul, Siranee Saengsanon, Wilasinee PakviwatAbstract:Purpose: The purpose of this study was to evaluate the Fracture Resistance of endodontically treated teeth between those with four walls and those with three walls of remaining coronal tooth structure and the effect of the site of the missing coronal wall. Materials and Methods: Thirty-two endodontically treated second mandibular premolars were decoronated, leaving 3 mm above the cementoenamel junction (CEJ). A 0.5-mm-wide chamfer was prepared 1 mm above the CEJ. The teeth were randomly divided into four groups. Group 1 had four walls of coronal tooth structure, whereas groups 2, 3, and 4 had only three walls, missing the buccal, lingual, and mesial wall, respectively. The cast dowel and cores and crowns (Ni–Cr alloy) were cemented with zinc phosphate cement. A compressive load was applied 45° to the long axis, 2 mm below the buccal cusp, with an Instron machine until failure at a crosshead speed of 5 mm/min. Failure load (kg) and mode of failure were recorded. Data were analyzed with one-way ANOVA and Scheffe tests (p < 0.05). Results: Group 1 had the highest Fracture Resistance (1190.3 ± 110.5 kg), significantly different from the other groups (p < 0.05) (group 2: 578.5 ± 197.4 kg; group 3: 786.6 ± 132.8 kg; group 4: 785.4 ± 289.9 kg). There were no significant differences among the test groups. The mode of failure in group 1 was a horizontal root Fracture, whereas that of the other groups was either vertical or oblique Fracture. Conclusions: Teeth with four walls of remaining coronal dentine had significantly higher Fracture Resistance than teeth with only three walls. The site of the missing coronal wall did not affect the Fracture Resistance of endodontically treated teeth.
Carlos Jose Soares - One of the best experts on this subject based on the ideXlab platform.
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Fracture Resistance and stress distribution of simulated immature teeth after apexification with mineral trioxide aggregate
International Endodontic Journal, 2014Co-Authors: Manoel Britojunior, Carlos Jose Soares, Rodrigo Dantas Pereira, Crisnicaw Verissimo, Andre Luis Fariaesilva, Carla Cristina Camilo, Manoel Damiao SousanetoAbstract:Aim To evaluate the effect of adhesive restorations on Fracture Resistance and stress distribution in teeth with simulated immature apices and apical plugs of mineral trioxide aggregate (MTA). Methodology Sixty bovine incisors were sectioned 8 mm above and 12 mm below the cemento-enamel junction (CEJ). The root canal was enlarged using a diamond bur, resulting in remaining root canal walls with 0.1–0.2 mm of thickness. A 5-mm apical plug of MTA was placed and the teeth were restored according to the following groups: GP – the root canal was filled with gutta-percha and endodontic sealer; CR – the root canal was filled with light-cured composite resin inserted incrementally; FP – a fibre post was cemented into the root canal; and RFP – the fibre post was relined with composite resin prior to the cementation into the root canal. A load was applied on the crown of all teeth at 135° to their long axis until Fracture. Data was analysed by one-way anova and SNK tests (α = 0.05), whilst the Fracture pattern was evaluated according to the position of the Fracture. Stress distributions in the restored teeth were verified by finite element analysis. Results Teeth restored with fibre posts and relined fibre posts were associated with the highest Fracture Resistance, whilst the GP group had the lowest values. GP and RC groups had similar Fracture Resistance values (P = 0.109). All Fractures types involved the cervical and middle thirds of roots. The GP model had high levels of stress concentration in the cervical and middle thirds of roots. No difference was found amongst the stress concentration in the RC, FP and RFP models. Conclusion Restorative protocols alter the Fracture Resistance and stress distribution of immature teeth after placement of MTA apical plugs.
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effects of post system and length on the strain and Fracture Resistance of root filled bovine teeth
International Endodontic Journal, 2008Co-Authors: Paulo Cesar Freitas Santosfilho, Carolina Guimaraes Castro, Gisele Rodrigues Da Silva, Roberto Elias Campos, Carlos Jose SoaresAbstract:Aim To investigate ex vivo the effects of different post systems and lengths on the strain and Fracture Resistance of root-filled teeth. Methodology One hundred and thirty-five bovine incisors were sectioned 15 mm from their apices, root-filled and divided into three groups (n = 45): fibreglass post; prefabricated steel post; cast post and core. Each group was divided into three subgroups (n = 15) according to the post length: 5.0 mm; 7.5 mm; 10.0 mm. All teeth were restored with metal crowns. For strain-gauge measurement, two strain gauges per sample were used. The Fracture Resistance (N) was measured and the data were analysed with two-way analyses of variance, followed by the Tukey’s HSD test (α = 05). Results For all posts, decreased lengths resulted in increased microstrain values. However, the fibreglass posts were associated with lower increases when compared with cast post and cores and prefabricated steel posts, which showed microstrain values two times higher when the post length was 5.0 mm. The two-way analyses of Fracture Resistance values revealed that post length was statistically significant for the metal posts and not significant for the fibreglass post. The Fracture mode analysis indicated that all groups tended to demonstrate root Fractures in groups restored with metal posts and resin core Fractures in groups restored with fibreglass posts. Conclusions The cast post and core when the length was 10.0 mm had the highest Fracture Resistance; however, the fibreglass post was effective with the three post lengths, with higher Fracture Resistance than metal posts when the length was 5.0 mm.
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influence of restorative technique on the biomechanical behavior of endodontically treated maxillary premolars part i Fracture Resistance and Fracture mode
Journal of Prosthetic Dentistry, 2008Co-Authors: Paulo Vinicius Soares, Paulo Cesar Freitas Santosfilho, Luis Roberto Marcondes Martins, Carlos Jose SoaresAbstract:Statement of problem Unresolved controversy exists concerning the preferred cavity design and restorative technique used to restore endodontically treated maxillary premolars to improve their Resistance to Fracture under occlusal load. Purpose The purpose of this study was to evaluate the Fracture Resistance, stress distribution, and cusp deformation of endodontically treated human maxillary premolars restored with different materials. The study is divided into 2 parts. In Part I, Fracture Resistance and Fracture mode were determined. Material and methods Seventy noncarious human maxillary premolars were selected and divided into 7 groups (n=10). The control group, ST, consisted of sound unprepared teeth. Teeth in the other 6 groups were endodontically treated and each received 1 of 2 cavity preparation designs: MODd, direct mesio-occlusal-distal preparation; MODi, indirect mesio-occlusal-distal preparation. Teeth were restored with 4 types of material: AM, MODd restored with amalgam; CR, MODd restored with composite resin; LPR, MODi restored with laboratory-processed composite resin; and LGC, MODi restored with leucite-reinforced glass ceramic. The Fracture Resistance (N) was assessed under compressive load in a universal testing machine. The data were analyzed by 1-way ANOVA and the Tukey HSD test (α =.05). Fracture modes were recorded based on the degree of tooth structure involvement and restoration damage. Results Statistical analysis showed that the ST group presented the highest Fracture Resistance values. The restored groups showed significantly higher Fracture Resistance values compared to the nonrestored groups. The groups restored with adhesive techniques (LPR, CR, and LGC) presented significantly higher Fracture Resistance values than the group restored with the nonadhesive technique (AM) ( P Conclusions Teeth with the greatest amount of remaining tooth structure and those restored using adhesive technology showed higher Fracture Resistance values. There was great variation in the type of Fracture among groups.
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influence of root embedment material and periodontal ligament simulation on Fracture Resistance tests
Brazilian Oral Research, 2005Co-Authors: Carlos Jose Soares, Eliane Cristina Gava Pizi, Rodrigo Borges Fonseca, Luis Roberto Marcondes MartinsAbstract:The aim of this study was to evaluate the influence of the embedment material and periodontal ligament simulation on Fracture Resistance of bovine teeth. Eighty bovine incisor teeth were randomized into 8 groups (n = 10), embedded in acrylic or polystyrene resin using 4 types of periodontal ligament simulation: 1 - absence of the ligament; 2 - polyether impression material; 3 - polysulfide impression material; 4 - polyurethane elastomeric material. The specimens were stored at 37°C and 100% humidity for 24 hours. Specimens were submitted to tangential load on the palatal surface at 0.5 mm/minute crosshead speed until Fracture. The Fracture modes were analyzed as follows: 1 - coronal Fracture; 2 - cemento-enamel junction Fracture; 3 - partial root Fracture; 4 - total root Fracture. Statistical analyses by two-way ANOVA and Tukey's test were applied (p < 0.05). The results showed that root embedment method and periodontal ligament simulation have a significant effect on Fracture Resistance. Artificial periodontal ligament modified the Fracture modes.
Marc Schmitter - One of the best experts on this subject based on the ideXlab platform.
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the flexural strength of cad cam polymer crowns and the effect of artificial ageing on the Fracture Resistance of cad cam polymer and ceramic single crowns
Journal of Materials Science: Materials in Medicine, 2020Co-Authors: Anna Winter, Axel Schurig, Engelke Rasche, Franziska Rosner, Lisa Kanus, Marc SchmitterAbstract:The purpose of this study was to investigate the Fracture Resistance, flexural strength and Weibull modulus of an innovative CAD/CAM polymer and to compare its Fracture Resistance with that of glass ceramics. A total of 32 (n = 16 IPS e.max CAD (LIDI); n = 16 LuxaCam Composite (LUXA)) first mandibular molar crowns were fabricated and cemented onto metal dies by use of luting composite. Half of the specimens were loaded until Fracture without prior artificial ageing. The other half were subjected to thermal (5°/55 °C) and mechanical (1,200,000 cycles, 80 N) cycling before Fracture loading. Scanning electron microscopy was used to analyse Fracture behaviour. A three-point bending test of the flexural strength of LUXA was performed according to ISO 6872:2008. Data were analysed by means of the Kolmogorov–Smirnov test, Mann–Whitney U-test (p < 0.05) and Weibull statistical analysis. Initial Fracture Resistance of LIDI was significantly higher than that of LUXA. However, the initial Fracture Resistance of LIDI decreased significantly after artificial ageing. After ageing, Fracture Resistance was 1050.29 ± 325.08 N for LUXA and 1250.09 ± 32.53 N for LIDI. Three-point bending test yielded a mean flexural strength value for LUXA of 145.28 ± 18.21 MPa and a Weibull modulus of m = 9.51. Polymer-based material tested in this study had a lower Fracture Resistance than that of the glass-ceramic material. Fracture Resistance and flexural strength of LuxaCam Composite are sufficient for use in the first molar region. The mechanical properties of this innovative polymer-based material indicate it can be used in the first molar region as a suitable alternative to glass ceramics. Further clinical studies are required to confirm this.
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influence of surface treatment on the in vitro Fracture Resistance of zirconia based all ceramic anterior crowns
Dental Materials, 2015Co-Authors: Marc Schmitter, G Lotze, Wolfgang Bomicke, Stefan RuesAbstract:Abstract Objectives The purpose of this study was to assess the effect of surface treatment on the Fracture Resistance of zirconia-based all-ceramic anterior crowns. Methods Sixty-four zirconia-based all-ceramic anterior crowns, veneered by use of a press-on technique, were produced. For 48 crowns intraoral adjustment was simulated (A-group), 16 crowns remained unadjusted (WA-group). The adjusted area was then treated in three ways: 1. no further surface treatment; 2. polishing, with irrigation, using polishers interspersed with diamond grit for ceramics; and 3. polishing and glaze firing. Half of the specimens were loaded until Fracture in an universal testing device without artificial ageing; the other crowns underwent thermocycling and chewing simulation before ultimate-load testing. Explorative statistical analysis was performed by use of non-parametric and parametric tests. In addition, Fracture-strength tests according to ISO 6872 were performed for veneer ceramic subjected to the different surface treatments. Finite element analysis was also conducted for the crowns, and surface roughness was measured. Results Crowns in the A-group were more sensitive to aging than crowns in the WA-group (p = 0.038). Although both polishing and glaze firing slightly improved the Fracture Resistance of the specimens, the Fracture Resistance in the WA-group (initial Fracture Resistance (IFR): 652.0 ± 107.7 N, remaining Fracture Resistance after aging (RFR): 560.6 ± 233.3 N) was higher than the Fracture Resistance in the A-group (polished: IFR: 477.9 ± 108.8 N, RFR: 386.0 ± 218.5 N; glaze firing: IFR: 535.5 ± 128.0 N, RFR: 388.6 ± 202.2 N). Surface roughness without adjustment was Ra = 0.1 μm; for adjustment but without further treatment it was Ra = 1.4 μm; for adjustment and polishing it was Ra = 0.3 μm; and for adjustment, polishing, and glazing it was Ra = 0.6 μm. Stress distributions obtained by finite element analysis in combination with Fracture strength tests showed that Fractures most probably originated from the occlusal surface. Significance To improve Fracture Resistance and reduce the incidence of failure, extensive occlusal adjustment of veneered anterior zirconia restorations should be avoided. Neither polishing nor glazing could restore the Fracture Resistance to the level maintained with unadjusted crowns.
Siriporn Arunpraditkul - One of the best experts on this subject based on the ideXlab platform.
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Fracture Resistance of endodontically treated teeth three walls versus four walls of remaining coronal tooth structure
Journal of Prosthodontics, 2009Co-Authors: Siriporn Arunpraditkul, Siranee Saengsanon, Wilasinee PakviwatAbstract:Purpose: The purpose of this study was to evaluate the Fracture Resistance of endodontically treated teeth between those with four walls and those with three walls of remaining coronal tooth structure and the effect of the site of the missing coronal wall. Materials and Methods: Thirty-two endodontically treated second mandibular premolars were decoronated, leaving 3 mm above the cementoenamel junction (CEJ). A 0.5-mm-wide chamfer was prepared 1 mm above the CEJ. The teeth were randomly divided into four groups. Group 1 had four walls of coronal tooth structure, whereas groups 2, 3, and 4 had only three walls, missing the buccal, lingual, and mesial wall, respectively. The cast dowel and cores and crowns (Ni–Cr alloy) were cemented with zinc phosphate cement. A compressive load was applied 45° to the long axis, 2 mm below the buccal cusp, with an Instron machine until failure at a crosshead speed of 5 mm/min. Failure load (kg) and mode of failure were recorded. Data were analyzed with one-way ANOVA and Scheffe tests (p < 0.05). Results: Group 1 had the highest Fracture Resistance (1190.3 ± 110.5 kg), significantly different from the other groups (p < 0.05) (group 2: 578.5 ± 197.4 kg; group 3: 786.6 ± 132.8 kg; group 4: 785.4 ± 289.9 kg). There were no significant differences among the test groups. The mode of failure in group 1 was a horizontal root Fracture, whereas that of the other groups was either vertical or oblique Fracture. Conclusions: Teeth with four walls of remaining coronal dentine had significantly higher Fracture Resistance than teeth with only three walls. The site of the missing coronal wall did not affect the Fracture Resistance of endodontically treated teeth.
Suchit Khetarpal - One of the best experts on this subject based on the ideXlab platform.
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ex vivo Fracture Resistance of endodontically treated maxillary central incisors restored with fiber reinforced composite posts and experimental dentin posts
Journal of Conservative Dentistry, 2011Co-Authors: Ambica Kathuria, Mahendran Kavitha, Suchit KhetarpalAbstract:Aim : To compare the Fracture Resistance of teeth restored with fiber-reinforced composite (FRC) posts and experimental dentin posts milled from human root dentin. Materials and Methods : Thirty maxillary central incisors were divided into three groups of ten each. Twenty teeth were restored with FRC posts and solid dentin posts and numbered as Groups 2 and 3 respectively while Group 1 acted as the control, without any post. The teeth were loaded at 135° angle to their long axes after core build-up and the failure loads were recorded. Results : One-way Analysis of Variance (ANOVA) and Bonferroni multiple comparisons revealed a significant difference among test groups with the control group showing the highest Fracture Resistance, followed by the dentin post group and lastly the FRC post group. Conclusions : Teeth restored with dentin posts exhibited better Fracture Resistance than those restored with FRC posts.
